Liquid supply pump

ABSTRACT

A pump assembly to supply liquid at a low pressure to an apparatus consists of a vacuum activated fuel lift device wherein fuel from a submerged or raised fuel supply tank is caused to flow by ambient pressure into a chamber. As a centrifugal pump empties the chamber it creates a partial vacuum within the chamber which acts on a diaphragm device subsequently opening a valve which causes liquid stored at ambient pressure to enter the partially evacuated chamber. Means are provided to open the chamber to atmosphere when the pump reservoir is filled to capacity.

Umted States Patent w13,5s2,227

[72] inventors Wallace W. Velie 2,786,420 3/1957 Kenney 415/26 WoodlandHills; 2,945,446 7/1960 Mason et al. 4l5/24X Kimble F. Tesh, Sepulveda,both of, Calif. Primary Examiner camon R. Croyle {g 323 3 I 969Assistant ExaminerRichard E. Gluck [45 Pawmcd June I 1971 Anorneys--L.Lee Humphnes and Thomas S. MacDonald {73] Assignee North AmericanRockwell Corporation [54] LIQUID SUPPLY PUMP 7 Claims, 5 Drawing Figs.

[52] US. Cl 415/24, ABSTRACT; A pump assembly to supply liquid at a lowpres- 415/26 sure to an apparatus consists of a vacuum activated fuellift [51] lnt.Cl ..F0lb 25/00, d i wherein f l f a submerged or raised fl Supply Fold F03d tank is caused to flow by ambient pressure into achamber. As [50] Fleld of Search 417/205, 3 cemrifugal pump empties thechamber it creates a partial 200, 40, 249, 253, 2! L5; 415/24, 1 2vacuum within the chamber which' acts on a diaphragm device subsequentlyopening a valve which causes liquid stored at [56] References cuedambient pressure to enter the partially evacuated chamber. UNITED STATESPATENTS Means are provided to open the chamber to atmosphere when2,322,910 6/ l 943 Adney et al 4l5/24X the pump reservoir is filled tocapacity.

uoum SUPPLY PUMP BACKGROUND OF THE INVENTION There are many types ofvacuum operated pumps on the market, particularly in the automotivefield. These pumps invariably derive their vacuum source from the intakemanifolds of an internal combustion engine. A typical vacuum pumpjustdescribed is the subject of U.S. Pat. No. l,62l,8l7. This patent uses afloat assembly that actuates three different shutoff valves. A pendulumaction controls two valves on one arm of the float assembly extendingfrom a pivot and one valve on the opposite arm so that when the floatchamber is depleted the float position is towards the bottom of thefloat chamber thereby allowing liquid from a remote tank to enter thechamber. The force causing the liquid to flow into the float chamber isa vacuum created by the engine manifold which is controlled by a-valveon one side of the fulcrum action of the float. As the float'comes up inthe chamber the vacuum source is shut down and the liquid source is shutoff. At the same time the valve isolating the chamber from theatmosphere is open, allowing atmospheric pressure to enter the chamberwhich causes the liquid to move to a second chamber for admittance tothe intake manifold of the engine.

The foregoing prior art pump as well as similar types of pump devicesuse mechanically actuated shutoff valves as part of the pump which areoperable by levers cantilevered off a float valve which is swivellyhinged to the body of the chamber. If the mechanically actuated valveshould not completely shut off the vacuum line from the engine, then thefloat chamber is in danger of over filling, i.e., dumping liquidoverboard through the valve vents. The pumps additionally are hinderedby wear which multiples with each additional mechanically actuatedvalve.

Other known vacuum pumps in the prior art disclose minor variations ofthe above described patent. These devices all require a separate vacuumpumping source and all of them use mechanically actuatable shutoffvalves that are controlled by a float suspended in liquid.

A disadvantage in conventional vacuum pumps is the sensitivity of theshutoff valve between the liquid supply source and the pump. The valveis subject to malfunction due either to wear or toforeign objects beingtrapped between the seat of the valve and the valve body. Obviously, ifthe mechanically actuated shutoff valves should encounter a problem, thesensitive balance of liquid within the chamber is upset.

Another disadvantage would be the danger of overflow through the ventsdue to float assemblymalfunctions causing a potential fire hazard, etc.

Still another disadvantage in the prior art is encountered when a vacuumpumping apparatus is employed wherein liquid is prevented from enteringthe float chamber from a supply source by blockage of the line to theexternal vacuum source and venting the float chamber to atmosphere. Apositive head fuel supply cannot be used since there is nothing to stopflow through the apparatus and out through the vents open to theatmosphere. The fuel supply source must be physically located below thecarburetor.

A further disadvantage exists in a pumping apparatus which directlyblocks the line from the fuel supply source to the pump. Operation ispossible with a positive head, however any leak or siphoning actionwithin the float chamber will empty the chamber.

Accordingly, it is an object of this invention to provide a vacuumliquid supply pump with a positive shutoff capability.

More particularly, it is an object of this invention to provide a vacuumliquid supply pump having a positive shutoff capability which does notrequire a separate vacuum supply and which includes a pneumaticallyoperated valve actuation device whichis not dependent upon positivemechanical float linkages to operate.

SUMMARY OF THE INVENTION The liquid supply pump basically is a vacuumfuel lift device having a low head liquid supply and a positive liquidshutoff capability. The device has utility in, for example, fuel burnerswhich will operate with the fuel supply tank either physically locatedabove or below the burner level. A particle vacuum is created when acentrifugal pump ejects liquid from a sealed chamber causing flow froman elevated or submerged storage tank into the chamber by atmosphericpressure. A float valve in an adjacent chamber will periodically ventthe pump assembly to ambient pressure when fuel level becomes sufficientwithin the second chamber. Ambient pressure will close a common vacuumoperated fuel shutoff valve shutting off the supply from the remotetank. .When the fuel in the float chamber becomes sufficiently low, thefloat valve will close permitting evacuation of the sealed chamber andsubsequent refilling from the fuel supply tank. The refilling process iscontinuously repeatable during pump operation. The liquid supply systemdisclosed is especially suited, for example, in an oil burner requiringa low pressure fuel supply system which is also capable of lifting fuelfrom a remotely located tank and providing a positive fuel shutoff toavoid fuel flooding or overflow. The pump is most suitable for use with,for example, oil burners having a pneumatic fuel atomizer system whichatomizes liquid for proper combustion.

When operating, one side of a positive shutoff valve actuator opposite ashutoff valve is evacuated. The differential pressure across thepneumatic piston causes it to move against a spring and to open thevalve communicating with a remotely located liquid supply tank. Ambientpressure in the supply tank causes the fuel to flow into the partiallyevacuated chamber. The liquid is subsequently pumped into an adjacentchamber containing a liquid level float and associated valve. The fuelis pumped into the chamber containing the float until the level reachesa point at which the float lifts a valve located in a barrier wallbetween the two chambers subjecting the sealed chamber being fed by theremotely located tank to ambient pressure, thereby causing the pneumaticpiston to move back to its normal position causing the valvecommunicating with the remotely located supply tank to be closed, thus,shutting off the supply from the tank to the sealed chamber. When thechamber containing the float is depleted due to action of a second pumpwhich pumps the liquid out of the float containing chamber, the valveattached to the float again closes, sealing the lower chamber therebycausing the pneumatic piston again to be affected by a lessening inpressure in the bottom chamber, thereby reopening the main supply valvestarting the cycle over again. A,

The vacuum lift pump continues to operate in a cycli fashion ashereinbefore described. When both chambers are full, the valvecontrolled by the float remains open, therefore the liquid merely flowsfrom the lower chamber to the upper chamber and back down to the lowerchamber until such a time as the upper chamber becomes depleted causingthe float to drop and the valve to be shut off, thereby triggering therefilling cycle.

An advantage over the prior art is the absence of mechanical linkagescontrolling the valve which causes the liquid to flow into one of twochambers.

Another advantage over the prior art is the absence of an externalvacuum source.

Still another advantage is the ability to locate the liquid supply tankeither above or below the pumping apparatus.

Yet another advantage is the fail-safe feature wherein any leakagewithin the vacuum pump automatically shuts off the supply from theliquid supply source to the pump thereby obviating any possibility of aleak.

Still another advantage is the capability to lift liquid under ambientpressure from a remote liquid supply source without resorting to closetolerance gear pumps and the like.

DESCRIPTION OF THE DRAWINGS The above-noted objects and furtheradvantages of the present invention will be more fully understood uponthe study of the following detailed description in conjunction with thedetailed drawings in which:

FIG. I is a partially cutaway plan view of the preferred embodiment ofthe invention;

FIG. 2 is a cutaway section taken along lines 2-2 of FIG. 1 showing theupper and lower chambers and their interrelationships;

FIG. 3 is a section taken along lines 3-3 of FIG. I showing the detailsof the float and valve combination;

FIG. 4 is an enlarged view of the pneumatic valve assembly whichcommunicates with and controls the flow of fluid from a remotely locatedtank to one of the supply chambers;

FIG. 5 is a view taken along lines 5-5 of FIG. 2 which shows the detailsof the pump which supplies an apparatus to be fed by the pump.

Referring now to FIGS. I and 2, the fluid supply pump generallydesignated as consists of housing 12 which basically encloses a lowerchamber 14 (FIG. 2) and an upper chamber 16. The cutaway section shownin FIG. 2 reveals the basic components including a fuel supply inlet 18which communicates with a remotely located liquid supply tank (notshown), a valve 20, and a pressure sensitive diaphragm 32. A pair ofcommonly driven axially aligned centrifugal pumps 40 and 50 areconnected to a common drive shaft 52. The shaft 52 is connected directlyto the radially extending impeller blades 53 of centrifugal pump 50which extend into an annulus 57. The drive shaft 52 extends below pump50 and is splined onto a shaft 56 at union 54. A pin 55 transmits therotary driving force to pump 40 which has impeller blades 42 extendinginto the cavity or annulus 44. A passageway 46 communicates at one endwith annulus 44 and empties into the upper chamber 16 at the other endexiting at port 48. The upper chamber 16 essentially houses the floatassembly 60 (FIG. 1) as well as the primary centrifugal pump assembly50. Float assembly 60 is comprised of a pair of arms 62 and 64 which arepivotably anchored to floor 13 by pivots 63 and 65. Integral with pivotarm 62 is a valve assembly 70 (FIG. 3) which is operably by floatassembly 60. The shutoff valve is adjustable by positioning a nut 74which is in threadable engagement with .a shaft 72.

Referring now to FIG. 4, the valve assembly 20 which communicates atinlet 18 directly with a liquid supply source (not shown) comprises aball valve 22, a spring 24 housed within a valve body 26 which slideswithin cylinder 27. The cylinder 27 has, at its free end, an inwardlyextending lip 28 which prevents the center body 26 from extendingthrough the body 27. The top of center body 26 contains a pair ofaxially extending conduits 21 and 23.

The controlling apparatus for the valve 20 is in the diaphragm assembly30 which is attached to the intermediate wall 13 and consists of anupper plate 31, a flexible diaphragm 32 and a lower support plate 33. Acentral shaft 34 connects together plate 31, diaphragm 32, and lowerplate 33, as well as providing for an interconnecting pad 35 which isaligned with the valve body 26 by pin 36. A rubberlike washer 37 acts asa cushion for pad 35 and the end of the center body 26. Washer 37 alsoacts as a sealing surface or seat for the valve 20 while it is in aclosed position.

Ball valve 22 serves a very specialized purpose. If the remotely locatedliquid supply tank is physically located a relatively long distancebelow the pump and the impedance (resistance) of the conduit feedinginlet 18 is low, there is a possibility of a negative pressure withinchamber 14 occuring when the pump is shut down caused by the liquidreturning to the supply tank. If there were no check ball valve 22, therush of liquid back to the supply tank could deflect diaphragm assembly30 downward holding valve 20 open causing liquid to reverse itself fromthe normal direction of flow from chamber 16 back through port 48 intothe annulus 44, finally returning to chamber 14. Since the impedance inconduit 46 is higher than the impedance in the liquid supply feed line,there is a possibility of liquid being displaced by air within chamber14. Check valve 22 prevents or slows down the rush of liquid back to thesupply tank allowing valve 20 to close thereby obviating any possibilityof air entering chamber 14.

In operation, the liquid in chamber 14 is pumped by centrifugal pump 40from chamber 14 through internal conduit 46 and out port 48 into chamber16. Chamber 14 is always filled to capacity with liquid. As the pressurewithin chamber 14 diminishes, a partial vacuum occurs within the chamberdue to the pumping action of pump 40. This vacuum acts on diaphragmassembly 30 which deflects the diaphragm downwardly forcing valve body26 against spring 24 thereby uncovering ports 21 and 23'exposing them tochamber 14. The partial vacuum within the chamber acts to draw liquidunder ambient pressure from the remotely located supply tank in throughinlet 18, past ball valve 22 and out through ports 21 and 23, therebyreplenishing chamber 14 to capacity. As the level rises in the upperchamber 16 by the pumping action of centrifugal pump 40, the floatassembly 60 rises within the chamber. As seen in FIG. 3, as the floatassembly rises, the valve assembly is lifted off valve seat 76. Upperchamber 16 is exposed to atmospheric pressure through conduit or opening17. Since valve assembly 70 is in the communication with lower chamber14, the float assembly 60 lifts the valve off of valve seat 76 therebyexposing the lower chamber to atmospheric pressure. When this happens,the partial vacuum created in lower chamber 14 is lost, hence thediaphragm assembly returns to a normal position which recloses thespring biased valve assembly 20 thereby stopping the flow of liquid fromthe external liquid supply source. Air is discouraged from enteringchamber 14 by the coacting mechanism within both chambers.

The upper chamber 16 is evacuated by centrifugal pump assembly 50, seenmore clearly in FIG. 5. The impeller blades 53 force liquid out ofannulus 57, out through conduit 58 toward exit 59. Needle valve assembly80 meters liquid passing through conduit 58 into exit conduit 59dependent upon the operating pressure or flow desired. The needle valve82 is threadably engaged with housing 12 and is adjustable at port 15.

When the upper chamber 16 is evacuated by a centrifugal pump assembly50, the level of the float assembly 60 drops thereby closing valve 70which seals lower chamber 14 causing the diaphragm to again downwardlydeflect as the lower chamber is depleted thereby starting the fillingcycle over again.

When both chamber 14 and 16 are full, the valve assembly 70 remains openand the liquid is merely circulated from the lower chamber, through theupper chamber; down again into the lower chamber via opened valve 70until such a time as there is again a liquid demand from upper chamber16 which recycles the pump.

It should be noted here that, if the float assembly 60 is lodged in theopen position whereby valve 70 cannot close, then the lower chamber 14is exposed to atmospheric pressure which will maintain the diaphragmassembly 30 in the normal position thereby preventing further liquidfrom the supply tank from entering the pump through the valve assembly20 thereby providing a fail-safe condition. Thus, the pump assemblycannot overflow.

We claim:

1. A liquid supply pump comprising:

a housing,

a first chamber within said housing having a liquid inlet meanscommunicating with said chamber, a second chamber within said housing inflow communication with said first chamber, said second chamber having aliquid exit means,

a first circulating pump means within said first chamber for pumpingliquid from said first chamber to said second chamber,

a second pump means within said second chamber to pump liquid from saidsecond chamber through said liquid exit means,

pressure sensitive valve means in said first chamber, said valve meansbeing responsive to change in pressure to admit liquid through saidliquid inlet means when the pressure within said first chamber is belowambient pressure, A

liquid level sensing means within said second chamber, and,

a second valve means connected to said sensing means, said valve beingincommunication with said first chamber so as to expose said first chamberto ambient pressure when the liquid level within said second chamber isat a predetermined level thereby shutting off the flow through saidinlet means to said first chamber.

2. The invention as set forth in claim 1 wherein said first chamber isbelow said second chamber, said first and second chamber being dividedby a common barrier.

3. The invention as set forth in claim 2 wherein said pressure sensitivevalve means in said first chamber comprises a diaphragm assemblyconnected to said barrier responsive to pressure within said chamber,said diaphragm being connected to a valve assembly in communication withsaid fluid inlet means whereby a pressure below ambient pressure causesa deflection of the diaphragm which actuates said valve to cause liquidunder ambient pressure from a liquid supply source to enter said firstchamber.

4. The invention as set forth in claim 3 wherein said liquid supplysource is a remotely located tank, its position being either above orbelow said liquid supply pump without adversely affecting the operationof the pump.

5. The invention as set forth in claim 1 wherein said first and secondpumps are centrifugal pumps and are attached to a common shaft extendingthrough said first and second chamber.

6. The invention as set forth in claim I wherein said first circulatingpump means creates an internal vacuum within said first chamber whensaid pump lowers the liquid level within said first chamber during pumpactuation.

7. The invention as set forth in claim I wherein said first circulatingpump means within said first chamber pumps liquid through a channelwithin the sidewall of said first and second chamber, said channelconnected at one end to an annulus of said first pump and exiting at itsother end into said second chamber.

1. A liquid supply pump comprising: a housing, a first chamber withinsaid housing having a liquid inlet means communicating with saidchamber, a second chamber within said housing in flow communication withsaid first chamber, said second chamber having a liquid exit means, afirst circulating pump means within said first chamber for pumpingliquid from said first chamber to said second chamber, a second pumpmeans within said second chamber to pump liquid from said second chamberthrough said liquid exit means, pressure sensitive valve means in saidfirst chamber, said valve means being responsive to change in pressureto admit liquid through said liquid inlet means when the pressure withinsaid first chamber is below ambient pressure, liquid level sensing meanswithin said second chamber, and, a second valve means connected to saidsensing means, said valve being in communication with said first chamberso as to expose said first chamber to ambient pressure when the liquidlevel within said second chamber is at a predetermined level therebyshutting off the flow through said inlet means to said first chamber. 2.The invention as set forth in claim 1 wherein said first chamber isbelow said second chamber, said first and second chamber being dividedby a common barrier.
 3. The invention as set forth in claim 2 whereinsaid pressure sensitive valve means in said first chamber comprises adiaphragm assembly connected to said barrier responsive to pressurewithin said chamber, said diaphragm being connected to a valve assemblyin communication with said fluid inlet means whereby a pressure belowambient pressure causes a deflection of the diaphragm which actuatessaid valve to cause liquid under ambient pressure from a liquid supplysource to enter said first chamber.
 4. The invention as set forth inclaim 3 wherein said liquid supply source is a remotely located tank,its position being either above or below said liquid supply pump withoutadversely affecting the operation of the pump.
 5. The invention as setforth in claim 1 wherein said first and second pumps are centrifugalpumps and are attached to a common shaft extending through said firstand second chamber.
 6. The invention as set forth in claim 1 whereinsaid first circulating pump means creates an internal vacuum within saidfirst chamber when said pump lowers the liquid level within said firstchamber during pump actuation.
 7. The invention as set forth in claim 1wherein said first circulating pump means within said first chamberpumps liquid through a channel within the sidewall of said first andsecond chamber, said channel connected at one end to an annulus of saidfirst pump and exiting at its other end into said second chamber.